24 



Analyses of Lchig/i district eminent materials. 



"Cement rock" in other parts of the United States. Certain 

 Portland cement plants, particularly in the western United 

 States, are using combinations of materials closely similar to 

 those in the Lehigli district. Analyses of the materials used at 

 several of these plants are given in Table III. 



Analyses of "cement rock" materials from the western United 



States. 



In addition to the "cement rocks 7 ' noted in this chapter, it is 

 necessary to call attention to the fact that many of the chalky 

 limestones discussed 1 on page 26 are sufficiently argillace- 



